The next time a viral infection starts spreading zombie-like madness across England (or wherever), we might put a halt to the plague before the sequel ever gets made. Our secret weapon will be a designer drug created by plugging some numbers into a mathematical formula. Rice University researchers have developed just such a formula, and it can show us exactly how to force a virus to mutate uncontrollably, to the point that the virus mutates itself out of existence.Evolution is a very complex phenomenon, affected by millions of variables and difficult to control precisely. At the purely mechanical level, however, we understand it quite well. The Rice research examined how viruses and bacteria mutate by exchanging genes and gene sets. Then they came up with a formula for several key factors: recombination rate, mutation rate and fitness function. If you know any two of the factors for a given organism, you can figure out the third. That means you can create a drug that will manipulate one of the factors and create a very specific outcome. One such outcome is called lethal mutagenesis. Using a designer drug, you increase the mutation rate so fast that the population undergoes what bioengineers call a "phase change" (they liken their formula in many ways to thermodynamics, hence the reference to phases of matter). Rice professor Michael Deem described the ultimate result:

"If the mutation, recombination or horizontal gene transfer rates are too high, the system delocalizes and gets spread all over sequence space."

I have no idea what that means, but I'm sure it isn't good news for the virus. It also makes for great sci-fi dialogue. Handsome Smuggler: Watch your horizontal transfer rate, kid. You don't want to delocalize the system. Adventuresome Farm Boy: Why not? Handsome Smuggler: Then we'll end up spread all over sequence space. Adventuresome Farm Boy: I made out with my sister. Image by: hans s.Forced evolution: Can we mutate viruses to death? [EurekAlert!]